Three-dimensional optical waveguide, method of manufacturing same, optical module, and optical transmission system

ABSTRACT

A three-dimensional optical waveguide is formed by laminating planar substrates such as a plurality of lens substrates and, an isolator substrate and a wavelength division multiplexing filter, the optical substrates at least include a waveguide substrate having a waveguide and a reflecting surface. In the three-dimensional optical waveguide, the planar substrates are positioned by markers integrally formed on at least two of the planar substrates. Light directed into the waveguide is reflected by a reflecting surface and passes through the lens substrates and the isolator substrate.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a three-dimensional opticalwaveguide, a method of manufacturing the same, an optical module, and anoptical transmission system for enhancing the performance of an opticaldevice.

[0003] 2. Related Art of the Invention

[0004] Conventionally, when a three-dimensional optical waveguide isformed, for example, in order that light traveling through a waveguideis output vertically with respect to the waveguide, as shown in FIG. 26,a planar filter 1006 such as a wavelength division multiplexing (WDM)filter is inserted in a groove 1002 obliquely formed in a planarwaveguide 1001, and the light reflected or transmitted by the planarfilter 1006 is oriented with respect to a light receiving element 1008,a lens system and another planar optical waveguide which are disposedspatially, thereby forming the three-dimensional optical waveguide.

[0005] However, in such a three-dimensional optical waveguide, spatialadjustment in each waveguide and the lens system is extremely difficult.For example, when a planar wavelength division multiplexing filter isinserted in a planar optical waveguide, it is necessary that theformation of the groove for supporting the wavelength divisionmultiplexing filter be performed extremely precisely. In addition, afterthe insertion of the wavelength division multiplexing filter into thegroove, a precise adjustment for fine positioning of the wavelengthdivision multiplexing filter is further required.

[0006] Therefore, when it is intended to enhance the performance byinserting an optical device such as an isolator in such athree-dimensional optical waveguide, since the number of parts requiringadjustment increases, the cost increases.

SUMMARY OF THE INVENTION

[0007] In view of the above-mentioned problem, an object of the presentinvention is to provide a three-dimensional optical waveguide, a methodof manufacturing the same, an optical module and an optical transmissionsystem that are low in cost and do not require complicated adjustment.

[0008] The 1st aspect of the present invention is a three-dimensionaloptical waveguide comprising a lamination of at least a planar substrate(1, 31, 51, 61, 71, 91, 301, 711, 1311, 1321, 1331) having a planaroptical waveguide (2, 12, 22, 32, 52, 62, 72, 92, 702, 712, 902, 1322,1332, 1342, 1352, 1362) and a planar substrate (3, 8, 10, 30, 33, 43,53, 63, 70, 73, 76, 93, 98, 300, 900, 1308, 1330, 1340, 1343, 1350)having a sheet optical element (4, 5, 6, 7, 9, 24, 34, 29, 44, 54, 64,74, 79, 94, 95, 96, 97, 209, 304, 404, 704, 904, 906, 909, 914, 919,1304, 1305, 1306, 1307, 1316, 1324, 1334, 1344, 1354, 1364).

[0009] The 2nd aspect of the present invention is a three-dimensionaloptical waveguide according to the 1st aspect, wherein the planarsubstrate having a sheet optical element is one of a lens layer, anisolator layer and a filter layer.

[0010] The 3rd aspect of the present invention is a three-dimensionaloptical waveguide according to the 2nd aspect, wherein the planarsubstrate having the planar waveguide, and the said one of the lenslayer, the isolator layer and the filter layer are integrally formed onforming glass.

[0011] The 4th aspect of the present invention is a three-dimensionaloptical waveguide according to the 2nd aspect or 3rd aspect, wherein areflecting surface is formed on the planar optical waveguide and lightpasses through the said one of the lens layer, the isolator layer andthe filter layer.

[0012] The 5th aspect of the present invention is a three-dimensionaloptical waveguide according to the 4th aspect, further comprising atleast one of a light receiving element and a light emitting element.

[0013] The 6th aspect of the present invention is a three-dimensionaloptical waveguide according to the 1st aspect, wherein the planarsubstrates are positioned with respect to each other by markersintegrally formed on at least two planar substrates.

[0014] The 7th aspect of the present invention is a method ofmanufacturing a three-dimensional optical waveguide comprising:

[0015] providing a plurality of planar substrates (3, 8, 10, 30, 33, 43,53, 63, 70, 73, 76, 93, 98, 300, 900, 1308, 1330, 1340, 1343, 1350),each having a planar optical waveguide;

[0016] forming a marker (101, 103) on each of the planar substrates (3,8, 10, 30, 33, 43, 53, 63, 70, 73, 76, 93, 98, 300, 900, 1308, 1330,1340, 1343, 1350) at a same time; and

[0017] laminating the planar substrates (3, 8, 10, 30, 33, 43, 53, 63,70, 73, 76, 93, 98, 300, 900, 1308, 1330, 1340, 1343, 1350) bypositioning the planar substrates by using the markers (101, 103).

[0018] The 8th aspect of the present invention is a method ofmanufacturing a three-dimensional optical waveguide according to the 7thaspect, wherein the markers have one of a concave or convex shape, andwherein before the planar substrates are laminated, the planarsubstrates are positioned by applying light to the markers and causingthe light to be reflected or transmitted by the markers.

[0019] The 9th aspect of the present invention is a method ofmanufacturing a three-dimensional optical waveguide according to the 8thaspect, wherein bottom surfaces of the markers are one of inclinedsurfaces, scattering surfaces and lens surfaces.

[0020] The 10th aspect of the present invention is an opticaltransmitter module, comprising:

[0021] an electric input terminal (1105);

[0022] a light emitting element (69, 89, 999, 1209, 1219, 1229, 1239,1249) connected to the electric input terminal (1105);

[0023] the three-dimensional optical waveguide according to the 3rdaspect, the waveguide transmitting light emitted from the light emittingelement (69, 89, 999, 1209, 1219, 1229, 1239, 1249); and

[0024] an optical output terminal (1107) outputting light transmittedthrough the three-dimensional optical waveguide.

[0025] The 11th aspect of the present invention is an optical receivermodule, comprising:

[0026] an optical input terminal (1117);

[0027] the three-dimensional optical waveguide according to the 3rdaspect connected to the optical input terminal (1117);

[0028] a light receiving element, that receives light (59, 99, 1109,1119, 1129, 1139, 1149) transmitted through the three-dimensionaloptical waveguide; and

[0029] an electric output terminal (1115) connected to the lightreceiving element.

[0030] The 12th aspect of the present invention is an opticaltransmitter and receiver module, comprising:

[0031] an electric input terminal (1105);

[0032] a three-dimensional optical waveguide including a lamination ofat least a planar substrate (3, 8, 10, 30, 33, 43, 53, 63, 70, 73, 76,93, 98, 300, 900, 1308, 1330, 1340, 1343, 1350) having a planar opticalwaveguide (2, 12, 22, 32, 52, 62, 72, 92, 702, 712, 902, 1322, 1332,1342, 1352, 1362), a planar substrate (3, 8, 10, 30, 33, 43, 53, 63, 70,73, 76, 93, 98, 300, 900, 1308, 1330, 1340, 1343, 1350) having anisolator (8, 98, 1108, 1118, 1128, 1308), and a planar substrate (3, 8,10, 30, 33, 43, 53, 63, 70, 73, 76, 93, 98, 300, 900, 1308, 1330, 1340,1343, 1350) having a wavelength division multiplexing filter;

[0033] a light emitting element (69, 89, 999, 1209, 1219, 1229, 1239,1249) connected to the electric input terminal (1105) and connected tothe three-dimensional optical waveguide;

[0034] a light receiving element (69, 89, 999, 1209, 1219, 1229, 1239,1249) connected to the three-dimensional optical waveguide;

[0035] an electric output terminal (1115) connected to the lightreceiving element (69, 89, 999, 1209, 1219, 1229, 1239, 1249); and

[0036] an optical input and output terminal (1115) connected to thethree-dimensional optical waveguide,

[0037] wherein an electric signal input from the electric input terminal(1105) is converted into an optical signal and transmitted from theoptical input and output terminal (1115), and an optical signal receivedby the optical input and output terminal (1115) is converted into anelectric signal and output to the electric output terminal.

[0038] The 13th aspect of the present invention is an opticaltransmission system for transmission and reception, comprising:

[0039] an optical transmitter module, including:

[0040] an electric input terminal;

[0041] a light emitting element connected to the electric inputterminal;

[0042] a three-dimensional optical waveguide having:

[0043] a lamination of at least a planar substrate having a planaroptical waveguide connected to the light emitting element and a planarsubstrate having a sheet optical element;

[0044] the waveguide is transmitting light emitted from the lightemitting element; and

[0045] an optical output terminal outputting light transmitted throughthe three-dimensional optical waveguide;

[0046] an optical fiber cable connected to the optical transmittermodule; and

[0047] an optical receiver module, including:

[0048] an optical input terminal;

[0049] a three-dimensional optical waveguide having:

[0050] a lamination of at least a planar substrate having a planaroptical waveguide connected to the optical input terminal and a planarsubstrate having a sheet optical element;

[0051] a light receiving element, that receives light transmittedthrough the three-dimensional optical waveguide; and

[0052] an electric output terminal connected to the light receivingelement;

[0053] the optical receiver module is connected to the optical fibercable.

[0054] The 14th aspect of the present invention is an opticaltransmission system for optical transmission and reception, comprising:

[0055] the optical transmitter and receiver module according to 12thaspect; and

[0056] an optical fiber cable connected to the optical transmitter andreceiver module.

BRIEF DESCRIPTION OF THE DRAWINGS

[0057]FIG. 1 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a first embodiment ofthe present invention.

[0058]FIG. 2 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a modification of thefirst embodiment of the present invention.

[0059]FIG. 3 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a second embodiment ofthe present invention.

[0060]FIG. 4 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a modification of thesecond embodiment of the present invention.

[0061]FIG. 5 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a third embodiment ofthe present invention.

[0062]FIG. 6 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a modification of thethird embodiment of the present invention.

[0063]FIG. 7 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a fourth embodiment ofthe present invention.

[0064]FIG. 8 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a modification of thefourth embodiment of the present invention.

[0065]FIG. 9 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a fifth embodiment ofthe present invention.

[0066]FIG. 10 is a cross-sectional view showing the structure of athree-dimensional optical waveguide according to a sixth embodiment ofthe present invention.

[0067] FIGS. 11(a) to 11(f) are cross-sectional views showing a markerformed in each substrate and used when the three-dimensional opticalwaveguide of the present invention is manufactured.

[0068] FIGS. 12(a) to 12(c) are schematic views showing a method ofmanufacturing the three-dimensional optical waveguide of the presentinvention.

[0069] FIGS. 13(a) to 13(c) are schematic views showing a modifiedmethod of manufacturing the three-dimensional optical waveguide of thepresent invention.

[0070] FIGS. 14(a) and 14(b) are schematic views showing a furthermethod of manufacturing the three-dimensional optical waveguide of thepresent invention.

[0071] FIGS. 15(a) and 15(b) are schematic views showing a still furthermethod of manufacturing the three-dimensional optical waveguide of thepresent invention.

[0072] FIGS. 16(a) and 16(b) are schematic views showing yet anothermethod of manufacturing the three-dimensional optical waveguide of thepresent invention.

[0073] FIGS. 17(a) to 17(d) are schematic views showing still anothermethod of manufacturing the three-dimensional optical waveguide of thepresent invention.

[0074] FIGS. 18(a) and 18(b) are schematic views showing a still furthermethod of manufacturing the three-dimensional optical waveguide of thepresent invention.

[0075]FIG. 19 is a schematic view showing the structure of an opticaltransmitter module of the present invention.

[0076]FIG. 20 is a schematic view showing the structure of an opticaltransmitter module of the present invention.

[0077]FIG. 21 is a schematic view showing the structure of an opticalreceiver module of the present invention.

[0078]FIG. 22 is a schematic view showing the structure of an opticalreceiver module of the present invention.

[0079]FIG. 23 is a schematic view showing the structure of an opticaltransmitter and receiver module of the present invention.

[0080]FIG. 24 is a schematic view showing the structure of anapplication of the optical transmitter and receiver module of thepresent invention.

[0081]FIG. 25 is a perspective view showing a concrete example of anoptical input terminal, an optical output terminal or an optical inputand output terminal of the present invention.

[0082]FIG. 26 shows the structure of the waveguide according to theprior art.

[0083] Explanation of Reference Numerals

[0084]1, 11 Waveguide substrate

[0085]2, 12 Waveguide

[0086]3, 10 Lens substrate

[0087]4, 9 Lens

[0088]8 Isolator substrate

[0089]13, 14 Reflecting surface

[0090]59, 99 Surface emitting laser

[0091]69, 89 Surface-mount photodiode

[0092]101, 103 Marker

[0093]102, 104 Bottom surface

[0094]105 Light source

[0095]106 Light receiver

[0096]107, 108 Image

[0097] Embodiments of the Invention

[0098] (First Embodiment)

[0099]FIG. 1 shows the cross-sectional structure of a three-dimensionaloptical waveguide according to a first embodiment of the presentinvention.

[0100] A waveguide substrate 1 as the planar substrate having a planarwaveguide of the present invention is formed of forming glass, and awaveguide 2 which is the planar optical waveguide of the presentinvention is formed on the top surface of the waveguide substrate 1. Atan end of the waveguide 2, a reflecting surface 13 which is thereflecting surface of the present invention comprising a mirror or thelike is formed. On the top surface of the waveguide substrate 1, a lenssubstrate 3 which is the planar substrate having a lens layer of thepresent invention is laminated. In the lens substrate 3, a lens 4 isintegrally formed of forming glass (the same for the lens substratedescribed below).

[0101] Above the lens substrate 3, a polarizer 5, a Faraday rotator 6and a polarizer 7 are laminated in this order. These elements constitutean isolator substrate 8 which is the planar substrate having an isolatorof the present invention. On the top surface of the isolator substrate8, a lens substrate 10 is laminated which is the planar substrate havinga lens layer of the present invention. In the lens substrate 10, a lens9 is integrally formed of forming glass. Above the lens layer 10, awaveguide substrate 11 which is the planar optical waveguide of thepresent invention is laminated. The waveguide substrate 11 is alsoformed of forming glass.

[0102] In a lower part of the waveguide substrate 11, a waveguide 12which is the planar optical waveguide of the present invention isformed. At an end of the waveguide 12, a reflecting surface 14 which isthe reflecting surface of the present invention comprising a mirror orthe like is formed. The reflecting surface 13, the lens 4, the lens 9and the reflecting surface 14 are disposed so that the horizontalpositions thereof are aligned in the vertical direction. The method ofposition alignment will be described later. The reflecting surface 13 isangled (inclined by 45°) so that light traveling along the horizontaldirection is made to travel in the vertical direction. The reflectingsurface 14 is angled (inclined by 45°) so that light traveling along thevertical direction is made to travel in the horizontal direction). Thesubstrates are bonded by an ultraviolet cure adhesive or the like.

[0103] In this description, it is assumed that the vertical directionand the horizontal (longitudinal) direction coincide with the verticaldirection and the horizontal (longitudinal) direction of FIG. 1 (thisapplies to the description that follows).

[0104] When such a three-dimensional optical waveguide is manufactured,as described above, precise position alignment is necessary between thewaveguide substrate 1 having the reflecting surface 13 and the lenssubstrate 3 having the lens 4, between the lens substrate 3 and the lenssubstrate 10 having the lens 9 and between the lens substrate 10 and theoptical waveguide substrate 11 having the reflecting surface 14. FIGS.11 to 12 are views for assistance in explaining the method of suchposition alignment.

[0105] First, a concave marker 101 as shown in FIG. 11(a) is formedintegrally with the substrates (the waveguide substrate 1, the lenssubstrate 3, the lens substrate 10, and the waveguide substrate 11) bypressing the forming glass. As shown in FIG. 11(a), the marker 101 has abottom surface 102 angled at 45°.

[0106] Next, with reference to FIGS. 12(a) to 12(c), the process ofaligning the substrates will be described with the waveguide substrate 1and the lens substrate 3 as an example.

[0107] The bottom surfaces 102 angled as described above are formed inthe same direction with respect to the direction of length of thesubstrates. The horizontal positions of the markers 101 formed on thesubstrates are determined so that predetermined spacings are provided inthe direction of length of the substrates (hereinafter, referred to asthe X direction), in the direction orthogonal to the X direction withinthe planes of the substrates (hereinafter, referred to as the Ydirection) and in the direction in which the substrates are laminated(the vertical direction, that is, the direction orthogonal to the X andthe Y directions, hereinafter, referred to as the Z direction). Forexample, the substrates are laminated so that, as shown in FIGS. 12(a)to 12(c), the position of the marker 101 formed in the waveguidesubstrate 1 and the position of the marker 101 formed in the lenssubstrate 3 are the same in the Y direction of the substrates, apredetermined spacing a is provided in the X direction and apredetermined spacing c is provided in the Z direction.

[0108] As shown in FIG. 12(a), the waveguide substrate 1 is disposedbelow, and the lens substrate 3 is disposed above the waveguidesubstrate 1 through an ultraviolet cure adhesive. Then, a light source105 emitting parallel light is disposed below the waveguide substrate 1,and a light receiver 106 such as a CCD camera is disposed above the lenssubstrate 3 and at a side of the laminated substrates. When parallellight is emitted from the light source 105, part of the emitted parallellight is reflected by the bottom surfaces 102 in parts where the markers101 are present, and the reflected part of the light reaches the lightreceiver 106 disposed at a side of the laminated substrates. At theparts where the markers 101 are absent, the emitted parallel light isall transmitted, and the transmitted light reaches the light receiver106 disposed above the lens substrate 3.

[0109]FIG. 12(b) shows images obtained from the light receiver 106disposed above the lens substrate 3 in this manner. Here, an image 108corresponds to the marker 101 formed in the waveguide 1, and an image107 corresponds to the marker 101 formed in the lens substrate 3. Theseimages are shown on the light receiver 106 as parts darker than anyperipheral part. Then, adjustment is made by moving the waveguidesubstrate 1 and the lens substrate 3 in the horizontal direction so thatthe positions of the images 107 and 108 in the Y direction coincide witheach other and the spacing between the images 107 and 108 in the Xdirection is the predetermined spacing a.

[0110]FIG. 12(c) shows images obtained from the light receiver 106disposed at a side of the laminated substrates as described above. Here,an image 116 corresponds to the marker 101 formed in the lens substrate3, and an image 117 corresponds to the marker 101 formed in thewaveguide substrate 1. These images are shown on the light receiver 106as parts brighter than any peripheral part. Then, adjustment is made bymoving the waveguide 1 and the lens substrate 3 in the Z direction sothat the spacing between the image 116 and the image 117 is thepredetermined spacing c. When the elements are brought intopredetermined position alignment, ultraviolet light is applied to thewaveguide substrate 1 and the lens substrate 3 to cure theultraviolet-cure adhesive filling the space between the waveguidesubstrate 1 and the lens substrate 3, thereby bonding the substrates 1and 3.

[0111] Likewise, position alignment is made between the lens substrate 3and the lens substrate 10 and between the lens substrate 10 and thewaveguide substrate 11. At this time, the position alignment between thelens substrate 3 and the lens substrate 10 is performed by an operationsimilar to the above-described one with the isolator substrate 8sandwiched between the lens substrate 3 and the lens substrate 10.

[0112] At this time, while the predetermined spacing a may be differentamong the substrates, it is determined so that the horizontal positionsof the reflecting surface 13, the lens 4, the lens 9 and the reflectingsurface 9 are aligned in the vertical direction when the substrates arelaminated.

[0113] Next, the operation performed when such a three-dimensionaloptical waveguide is used will be described.

[0114] The light directed into the waveguide substrate 1 travels throughthe waveguide 2, and is reflected upward by the reflecting surface 13 tobe incident on the lens 4. The light having exited from the lens 4passes through the isolator substrate 8 and the lens 9, is horizontallyreflected by the reflecting surface 4, and travels through the waveguide12.

[0115] By doing this, a low-cost and precise three-dimensional opticalwaveguide not requiring a complicated adjustment is provided.

[0116] While in the description given above, the substrates arepositioned so that the horizontal positions (in the X direction and inthe Y direction) of the markers 101 formed in the substrates are thesame in the Y direction and the predetermined spacing a is provided inthe X direction, the substrates may be positioned so that apredetermined spacing b is provided in the Y direction.

[0117] In the first embodiment, the lens substrate 10 is present betweenthe isolator substrate 8 and the waveguide substrate 11. However, whenthe light reflected by the reflecting surface 13 can be condensed on thereflecting surface 14 only by a lens 24 as shown in FIG. 2, the lenssubstrate 10 is unnecessary. In that case, similar effects to thosedescribed above are obtained.

[0118] While in the present embodiment, the light source 105 is disposedbelow the waveguide substrate 1 when position alignment between thewaveguide substrate 1 and the lens substrate 3 is performed, the lightsource 105 may be disposed at a side of the waveguide substrate 1 andthe lens substrate 3 as shown in FIG. 13(a). In that case, at the partsnot coinciding with the bottom surfaces 102 of the markers 101, theparallel light emitted from the light source 105 is transmitted to theopposite side of the waveguide substrate 1 and the lens substrate 3 asit is to reach the light receiver 106 disposed at a side of thewaveguide 1 and the lens substrate 3, and at the parts coinciding withthe bottom surfaces 102 of the markers 101, part of the parallel lightis reflected upward to reach the light receiver 106 disposed above thelens substrate 3.

[0119] Consequently, as the images obtained on the light receiver 106disposed above the lens substrate 3, as shown in FIG. 13(b), an image109 corresponding to the marker 101 of the lens substrate 3 and an image110 corresponding to the marker 101 of the waveguide substrate 1 areshown on the light receiver 106 as parts brighter than the peripheralpart. As described above, when the light source 105 is disposed at aside of the waveguide substrate 1 and the lens substrate 3, thewaveguide substrate 1 and the lens substrate 3 can be positioned inpredetermined positions in the horizontal direction by adjusting thespacing a between the image 109 and the image 110 similar to theabove-described case.

[0120]FIG. 13(c) shows images obtained from the light receiver 106disposed at a side of the waveguide substrate 1 and the lens substrate 3as described above. Here, an image 118 corresponds to the marker 101formed in the lens substrate 3, and an image 119 corresponds to themarker 101 formed in the waveguide substrate 1. These images are shownon the light receiver 106 as parts darker than the peripheral part.Then, adjustment is made by moving the waveguide 1 and the lenssubstrate 3 in the Z direction so that the spacing between the image 118and the image 119 is the predetermined spacing c. When the elements arebrought into predetermined position alignment, the waveguide 1 and thelens substrate 3 are bonded together similar to the above-describedcase.

[0121] While the concave markers 101 are used for the positioning of thesubstrates in the description given above, convex markers 103 may beused for the positioning. FIG. 11(d) shows a case where the bottomsurface 104 of the convex marker 103 is angled at 45°. FIG. 11(e) showsa case where the bottom surface 104 of the convex marker 103 has ascattering surface. FIG. 11(f) shows a case where the bottom surface 104of the convex marker 103 has a lens configuration.

[0122] When these convex markers 103 are used, the horizontal positionsand the vertical positions of the substrates can be adjusted similarlyto the case of the concave markers 101 with the spacing between eachsubstrate being fixed by a spacer (not shown) or filled with an adhesiveas described above and with the light source 105 being disposed below orat a side of the waveguide 1.

[0123] While in the description given above, the bottom surfaces of themarkers 101 and 103 are angled at 45°, they may be angled at a differentangle. In that case, by disposing the light receiver 106 so that thelight from the light source 105 is projected onto the light receiver 106upward or downward in a slanting direction with respect to thesubstrates, the spacing between each substrate can be similarly adjustedby observing the images shown on the light receiver 106.

[0124] While in the description given above, the markers 101 and 103 ofwhich bottom surfaces are inclined are used to perform the positioningof the substrates in the horizontal direction and the verticaldirection, it is considered to use markers 101 having bottom surfaces102 of a different configuration.

[0125] FIGS. 14(a) and 15(a) show examples of arrangement of theelements in a case where markers 101 of which bottom surfaces 102 have alens configuration are used. As shown in FIG. 14(a), a light source 111is a diffusing light source, and is disposed below the waveguidesubstrate 1 at a predetermined distance therefrom. The light receiver106 is disposed above the lens substrate 3. In the waveguide substrate1, a concave marker 101 having a bottom surface 102 of a lensconfiguration being concave when viewed from below is disposed, and inthe lens substrate 3, a concave marker 101 having a bottom surface 102of a lens configuration being convex when viewed from below is disposed.Here, the concave lens of the bottom surface 102 formed in the waveguidesubstrate 1 has a lens configuration and a refractive index that refractinto parallel light the diffused light emitted from the light source 111disposed at the predetermined distance from the waveguide substrate 1.

[0126] The lens configuration as a convex lens and the refractive indexof the bottom surface 102 formed in the lens substrate 103 are a lensconfiguration and a refractive index that condense the parallel lightincident on the bottom surface 102 of the lens substrate 3 on the lightreceiver 106 disposed above the lens substrate 3. The positions ofmarkers 101 of the substrates are the same both in the X direction andin the Y direction, or are predetermined positions. In this arrangement,when light is emitted from the light source 111, the light passesthrough the marker 101 of the waveguide substrate 1 and the marker 101of the lens substrate 3 to be condensed on the light receiver 106. Theimages obtained from the light receiver 106 at this time are shown inFIG. 14(b). That is, on the light receiver 106, an image 112 which is animage of the marker 101 itself is formed and an image 113 condensed bythe bottom surface 102 having a lens configuration is formed inside theimage 112. As described above, by adjusting the waveguide substrate 1 orthe lens substrate 3 in the horizontal direction so that the image 113is formed inside the image 112, positioning of the waveguide substrate 1and the lens substrate 3 in the horizontal direction can be performed.

[0127] By adjusting the spacing between the waveguide substrate 1 andthe lens substrate 3 so that the outside diameter of the image 113 onthe light receiver 106 is a predetermined value (that is, so that thelight emitted from the light source 111 is most excellently condensed onthe light receiver 106), adjustment (positioning in the verticaldirection) of the spacing between the waveguide substrate 1 and the lenssubstrate 3 can be made. While in the FIG. 14(b), the two images 112 and113 are situated side by side, these are images formed when anothermarkers 101 of the same type are disposed so as to be situated side byside on the substrates. The markers 101 may be disposed one by one oneach of the substrates as shown in FIG. 14(a).

[0128]FIG. 15(a) shows a modification of the structure of FIG. 14(a). Inthis case, the bottom surface 102 of the marker 101 formed in thewaveguide substrate 1 has a lens configuration being convex when viewedfrom below. The lens configurations as convex lenses and the refractiveindices of the bottom surface 102 formed in the waveguide substrate 1and the bottom surface 102 formed in the lens substrate 3 are lensconfigurations and refractive indices that condense the light emittedfrom the light source 111 on the light receiver 106 disposed above thelens substrate 3 by way of the bottom surface 102 of the waveguidesubstrate 1 and the bottom surface 102 of the lens substrate 3. On thelight receiver 106, images 114 and 115 are similarly formed as shown inFIG. 15(b), and the positioning of the waveguide substrate 1 and thelens substrate 3 in the horizontal and the vertical directions can beperformed similarly to the above-described case.

[0129] While FIGS. 14(a), 14(b), 15(a) and 15(b) are described withreference to examples using the concave markers 101, the above-describedapplies to cases where convex markers 101 are used as shown in FIG.11(f).

[0130] FIGS. 16(a) and 16(b) show a case in which the bottom surfaces102 of the markers 101 are scattering surfaces (see FIG. 11(b)). In thiscase, as shown in FIG. 16(a), the light receiver 106 and the lightsource 105 are disposed below the waveguide substrate so as to adjoineach other. When parallel light is emitted from the light source 105 inthis arrangement, the light is scattered at the scattering surfaces ofthe bottom surfaces 102 of the markers 101, and part of the scatteredlight reaches the light receiver 106 disposed below the waveguidesubstrate 1. FIG. 16(b) shows images light-received on the lightreceiver 106. Here, an image 120 corresponds to the marker 101 formed inthe lens substrate 3, and an image 121 corresponds to the marker 101formed in the waveguide substrate 1. By adjusting the distance betweenthe image 120 and the image 121 so as to be the predetermined spacing a,positioning of the substrates in the horizontal direction can beperformed.

[0131] FIGS. 17(a) to 17(d) show a case where the bottom surfaces 102 ofthe markers 101 are inclined scattering surfaces. In this case, as shownin FIG. 17(a), the light receiver 106 can be disposed below thewaveguide substrate 1, at a side of the waveguide substrate 1 and thelens substrate 3 or above the lens substrate. In this arrangement, thehorizontal positions or the vertical positions of the substrates can beadjusted by applying light from the light source 105 disposed below thewaveguide substrate 1.

[0132] For example, by disposing the light receiver 106 above the lenssubstrate 3 and at a side of the waveguide substrate 1 and the lenssubstrate 3, positioning of the substrates in the horizontal directionand positioning thereof in the vertical direction can be performed atthe same time like in the case shown in FIGS. 12(a) to 12(c). Moreover,by disposing the light receiver 106 below the waveguide substrate 1 andat a side of the waveguide substrate 1 and the lens substrate 3,positioning of the substrates in the horizontal direction andpositioning thereof in the vertical direction can also be performed atthe same time. FIG. 17(b) shows images shown on the light receiver 106disposed above the lens substrate 3. An image 122 corresponds to themarker 101 formed in the lens substrate 3, and an image 123 correspondsto the marker 101 formed in the waveguide substrate 1. FIG. 17(c) showsimages shown on the light receiver 106 disposed at a side of the lenssubstrate 3 and the waveguide substrate 1. An image 124 corresponds tothe marker 101 formed in the lens substrate 3, and an image 125corresponds to the marker 101 formed in the waveguide substrate 1. FIG.17(d) shows images shown on the light receiver 106 disposed below thewaveguide substrate 1. An image 126 corresponds to the marker 101 formedin the lens substrate 3, and an image 127 corresponds to the marker 101formed in the waveguide substrate 1.

[0133] As described above, when the bottom surfaces of the markers 101are inclined scattering surfaces, since the light receiver 106 can bedisposed in three directions with respect to the substrates, there isflexibility in the positioning method. For example, positioning can beperformed even when the laminated substrates do not transmit light asdescribed later. Positioning can be more precisely performed by makingthe adjustment while observing the light receivers 106 disposed in thethree directions at the same time.

[0134] Moreover, it is considered that the bottom surfaces 102 of themarkers 101 are inclined lens surfaces. In that case, as shown in FIGS.18(a) and 18(b), the light receiver 106 is disposed so as to be shiftedfrom the optical axis of the light source 105.

[0135] Moreover, it is considered that the bottom surfaces 102 of themarkers 101 are lens surfaces having scattering surfaces.

[0136] While in the description given above, the markers 101 formed inthe substrates are a combination of markers 101 of the same kind,positioning may be performed with a combination of markers 101 ofdifferent kinds. For example, positioning may be performed by forming inone substrate a marker 101 of which bottom surface 102 is inclined andforming in the other substrate a marker 101 of which bottom surface 102has a scattering surface. Moreover, positioning may be performed byforming in one substrate a marker 101 of which bottom surface 102 isinclined and forming in the other substrate a marker 101 of which bottomsurface 102 has a lens surface. Moreover, positioning may be performedby forming in one substrate a marker 101 of which bottom surface 102 hasa scanning surface and forming in the other substrate a marker 101 ofwhich bottom surface 102 has a lens surface. When a marker 101 having alens surface is combined, the light emitted from the light source 105 isnot necessarily strictly parallel.

[0137] While in the description given above, the method of positioningof the substrates is described as a case where positioning of thewaveguide substrate 1 and the lens substrate 3 is performed, it issimilarly applicable to a case where positioning of other substrates(that is, the planar substrates of the present invention) is performed.

[0138] While in the description given above, positioning is performed byapplying light from below the substrates, it is considered to applylight from above the substrates. For example, as shown in FIG. 1, whenunder a condition where the waveguide substrate 1, the lens substrate 3,the isolator substrate 8 and the lens substrate 10 are laminated, thewaveguide substrate 12 is further laminated on the lens substrate 10 andpositioning of the lens substrate 10 and the waveguide substrate 11 isperformed, the light source 105 and the light receiver 106 are disposedabove the waveguide substrate 11 and the light receiver 106 is disposedat a side of the lens substrate 10 and the waveguide substrate 11. Atthis time, markers 101 of which bottom surfaces 102 are inclinedscattering surfaces are used. When light is applied from above thewaveguide substrate 11, at the part where the markers 101 are absent,the light is reflected by the isolator substrate 11, and at the partwhere the markers 101 are present, the light is reflected sideward.Consequently, on the light receiver 106 disposed above the waveguidesubstrate 11, images similar to those shown in FIG. 12(b) are projected.On the light receiver 106 disposed at a side of the waveguide substrate11, images similar to those shown in FIG. 12(c) are projected. By doingthis, positioning of the substrates in the horizontal direction andpositioning thereof in the vertical direction can be performed at thesame time by applying light from above the substrates.

[0139] (Second Embodiment)

[0140] Next, a second embodiment of the present invention will bedescribed with reference to FIG. 3.

[0141] In the three-dimensional optical waveguide shown in FIG. 3, awaveguide substrate 31 has two waveguides 22 and 32. Here, the waveguide32 is disposed on the farther side from the plane of FIG. 3 so as to beparallel to the waveguide 22. The waveguide 22 has a reflecting surface313 at its end, and the waveguide 32 has a reflecting surface 333 at itsend. The lens substrate 33 has a lens 34 corresponding to the reflectingsurface 313 and a lens 304 corresponding to the reflecting surface 333.

[0142] Above the isolator substrate 8, a lens substrate 30 having a lens29 corresponding to the lens 34 is laminated, and above the lenssubstrate 30, a waveguide substrate 31 is laminated having a waveguide312 and a reflecting surface 314 disposed at an end of the waveguide 312and corresponding to the lens 29. Above the waveguide substrate 31, alens substrate 300 having a lens 209 corresponding to the lens 304 islaminated, and above a lens substrate 300, a waveguide substrate 301 islaminated having a waveguide 302 and a reflecting surface 324 disposedat an end of the waveguide 302 and corresponding to the lens 209.

[0143] Here, the reflecting surfaces 313 and 333 are angled at 45° likethe reflecting surface 13 in the first embodiment, and the reflectingsurfaces 314 and 324 are angled 45° like the reflecting surface 14 inthe first embodiment. Like in the first embodiment, the horizontalpositions of the reflecting surface 313, the lens 34, the lens 29 andthe reflecting surface 314 are aligned in the vertical direction, andthe horizontal positions of the reflecting surface 333, the lens 304,the lens 209 and the reflecting surface 324 are aligned in the verticaldirection.

[0144] Here, positioning of the waveguide substrate 31 and the lenssubstrate 33, positioning of the lens substrate 33 and the lenssubstrate 30, positioning of the lens substrate 30 and the waveguidesubstrate 31, positioning of the waveguide substrate 31 and the lenssubstrate 300 and positioning of the lens substrate 300 and thewaveguide substrate 301 are performed similarly to the first embodiment(the same applied to the embodiments described below).

[0145] By structuring the three-dimensional optical waveguide asdescribed above, the lights directed into the waveguides 22 and 32 ofthe waveguide substrate 31 are directed to the waveguides 312 and 302,respectively, by an action similar to that of the first embodiment. Asdescribed above, by laminating the planar substrates of the presentinvention and three-dimensionally forming two waveguides, a low-cost andhigh-performance three-dimensional optical waveguide not requiring acomplicated adjustment is provided.

[0146] While in the second embodiment, the lens substrate 30 is presentbetween the isolator substrate 8 and the waveguide substrate 31 and thelens substrate 300 is present between the waveguide substrate 31 and thewaveguide substrate 301, when it is possible that the light reflected bythe reflecting surface 313 is condensed on the reflecting surface 314only by the lens 44 and the light reflected by the reflecting surface333 is condensed on the reflecting surface 324 only by the lens 404 asshown in FIG. 4, the lens substrates 30 and 300 are unnecessary. In thatcase, similar effects to those described above are obtained.

[0147] While in the second embodiment, the waveguide 32 is disposed onthe farther side from the plane of FIG. 3 so as to be parallel to thewaveguide 22, the arrangement of the waveguides 22 and 32 is not limitedthereto. Similar effects to those described above are obtained from anyarrangement as long as the waveguides 22 and 32 are separately disposedon the same waveguide substrate 31 and the lights directed thereinto aredirected to the other waveguides 312 and 302, respectively.

[0148] The waveguides 22 and 32 are not necessarily present on the samewaveguide substrate 31 but may be present on different laminatedwaveguide substrates, and the waveguides 312 and 302 are not necessarilypresent on the waveguide substrates 31 and 301 but may be present on thesame waveguide substrate. In these cases, similar effects to thosedescribed above are obtained.

[0149] (Third Embodiment)

[0150]FIG. 5 shows the structure of a three-dimensional opticalwaveguide according to a third embodiment of the present invention.

[0151] In the three-dimensional optical waveguide of the presentembodiment, a surface emitting laser (VCSEL) 59 which is the lightemitting element of the present invention is disposed above the isolatorsubstrate 8, and a reflecting surface 513, a lens 54 and the surfaceemitting laser 59 are disposed so that the horizontal positions thereofare aligned in the vertical direction. Here, the structure of the partconstituted by a waveguide substrate 51, a lens substrate 53 and theisolator substrate 8 is similar to that of the first embodiment, anddescription thereof is omitted.

[0152] According to the above-described structure, the laser beamemitted from the surface emitting laser 59 passes through the isolatorsubstrate 8 and the lens 54 to be directed to the waveguide 52 of thewaveguide substrate 51. By doing this, a low-cost and high-performancethree-dimensional optical waveguide not requiring a complicatedadjustment is provided.

[0153] While in the third embodiment, the isolator substrate 8 ispresent between the lens substrate 53 and the surface emitting laser 59,the isolator substrate 8 is not necessarily present. In that case,similar effects to those described above are obtained.

[0154] While the above description is given with reference to an examplein which the surface emitting laser 59 is disposed above the isolatorsubstrate 8, as shown in FIG. 6, a surface-mount photodiode 69 which isthe light receiving element of the present invention may be disposedinstead of the surface emitting laser 59. FIG. 6 shows athree-dimensional optical waveguide comprising a waveguide substrate 61having a waveguide 62, a lens substrate 63 having a lens 64 and thesurface-mount photodiode 69. Here, the structure of the waveguidesubstrate 61 and the lens substrate 63 is similar to the above-describedstructure, and description thereof is omitted. In the structure shown inFIG. 6, the isolator substrate 8 may be laminated between the lenssubstrate 63 and the surface-mount photodiode 69.

[0155] (Fourth Embodiment)

[0156]FIG. 7 shows the structure of a three-dimensional opticalwaveguide according to a fourth embodiment of the present invention.

[0157] In the three-dimensional optical waveguide of the fourthembodiment, a waveguide substrate 71 has a waveguide 72, and a waveguide702 in a direction opposed to the waveguide 72. At an end of thewaveguide 72, a reflecting surface 713 is formed, and at an end of thewaveguide 702, a reflecting surface 733 is formed. Here, the reflectingsurfaces 713 and 733 are formed so as to be opposed to each other andeach angled at approximately 22.5° from the horizontal plane in adirection that forms a slope of a trapezoidal shape. On a lens substrate73 laminated above the waveguide substrate 71, a lens 74 and a lens 704are formed integrally with the lens substrate 73 so as to adjoin eachother.

[0158] Above the lens substrate 73, a wavelength division multiplexingfilter 76 which is the planar substrate having a filter layer of thepresent invention is laminated, and above the wavelength divisionmultiplexing filter 76, a lens substrate 70 having a lens 79 islaminated. Above the lens substrate 70, a waveguide substrate 711 islaminated having a waveguide 712 and a reflecting surface 714 formed atan end of the waveguide 712. Here, the reflecting surface 714 is angledat approximately 22.5° from the horizontal plane. When viewed from thereflecting surface 713, the lens 74, the lens 79 and the reflectingsurface 714 are aligned so as to be inclined toward the upper left by45° from the horizontal plane. When viewed from the reflecting surface733, the lens 704 is inclined by 45° from the horizontal direction in adirection slanting upward toward the right.

[0159] The operation of the three-dimensional optical waveguidestructured as described above will be described next.

[0160] The light traveling leftward in the horizontal direction throughthe waveguide 72 is reflected upward by the reflecting surface 713 at45° from the horizontal travel direction, and passes through the lens74. Part of the light having passed through the lens 74 passes throughthe wavelength division multiplexing filter 76 (that is, is sorted outby the wavelength division multiplexing filter), reaches the reflectingsurface 714 through the lens 79 to be reflected in the horizontaldirection, and travels leftward through the waveguide 712. The lightincluding the remaining wavelength component sorted out by thewavelength division multiplexing filter 76 is reflected at 45° from thehorizontal direction in a direction slanting downward toward the left atthe interface between the lens substrate 73 and the wavelength divisionmultiplexing filter 76, is reflected by the reflecting surface 733through the lens 704, and travels leftward in the horizontal directionthrough the waveguide 702.

[0161] As described above, according to the three-dimensional opticalwaveguide of the present embodiment, the light incident on the waveguide72 can be extracted after being separated between light travelingthrough the waveguide 712 and light traveling through the waveguide 702according to the wavelength component.

[0162] In the present embodiment, when it is possible that light issufficiently condensed on the reflecting surface 714 by the lens 74, thelens substrate 70 is unnecessary. In that case, similar effects to thosedescribed above are obtained.

[0163]FIG. 8 shows a modification of the present embodiment. In thismodification, above the lens substrate 70, a surface-mount photodiode 89is disposed instead of laminating the waveguide substrate 711. By doingthis, it is possible that, of the light incident on the waveguide 72,only the light of the wavelength component sorted out by the wavelengthdivision multiplexing filter 76 is directed into the surface-mountphotodiode 89 and the light of the wavelength component not sorted outby the wavelength division multiplexing filter 76 is directed into theother waveguide 702.

[0164] When the three-dimensional optical waveguide of the presentembodiment is formed, positioning of the substrates is performed byapplying light from above the three-dimensional optical waveguide asrequired. For example, in a case where positioning of the waveguidesubstrate 711 is performed under a condition where the waveguidesubstrate 71, the lens substrate 73, the wavelength divisionmultiplexing filter 76 and the lens substrate 70 are laminated as shownin FIG. 7, when the wavelength of the light emitted from the lightsource 105 does not pass through the wavelength division multiplexingfilter 76, the light source 105 is disposed above the waveguidesubstrate 711, and positioning of the waveguide substrate 711 isperformed by applying light from above by a method similar to thatdescribed in the first embodiment.

[0165] (Fifth Embodiment)

[0166]FIG. 9 shows the structure of a three-dimensional opticalwaveguide of the present invention according to a fifth embodiment.

[0167] The three-dimensional optical waveguide of the present embodimenthas on the left side thereof a three-dimensional optical waveguide wherea lens substrate 900 having a lens 919 is laminated above thethree-dimensional optical waveguide shown in the third embodiment (FIG.5), and has on the right side thereof the three-dimensional opticalwaveguide shown in the fourth embodiment (FIG. 8). Here, the thicknessof the lens substrate 900 is different between the left side and theright side thereof. The thickness of the right side of thethree-dimensional optical waveguide of the present embodiment is largerthan that of the left side by the thickness of a Faraday rotator 96 andthe thickness of a polarizer 97. Moreover, a wavelength divisionmultiplexing filter 906 is designed so as to reflect the wavelength ofthe light emitted from a surface emitting laser 99 and transmit thewavelength of the light incident from a waveguide 92. The elements otherthan these are similar to those of the third and the fourth embodiments,and description thereof is omitted.

[0168] In the three-dimensional optical waveguide having such astructure, the light traveling leftward through the waveguide 92 isreflected upward by a reflecting surface 913 at 45° from the horizontaltravel direction, passes through a lens 94, the wavelength divisionmultiplexing filter 906 and a lens 909, and reaches a surface-mountphotodiode 999. The light emitted from the surface emitting laser 99passes downward through the lens 919, an isolator substrate 98 and alens 914, is reflected rightward in the horizontal direction by areflecting surface 943, and is then reflected upward by a reflectingsurface 933 in a direction 45° from the direction of travel. The lightreflected by the reflecting surface 933 passes through a lens 904, isreflected at 45° in a direction slanting downward toward the right atthe interface between the wavelength division multiplexing filter 906and a lens substrate 93, passes through the lens 94, and reaches thereflecting surface 913. The light reflected rightward in the horizontaldirection by the reflecting surface 913 travels rightward through thewaveguide 92.

[0169] As described above, according to the present embodiment, alow-cost and high-performance three-dimensional optical waveguide isprovided that does not require a complicated adjustment although havinga complicated structure.

[0170] (Sixth Embodiment)

[0171]FIG. 10 shows the structure according to a sixth embodiment of thepresent invention.

[0172] The structure of the right side of the three-dimensional opticalwaveguide shown in FIG. 10 is similar to the structure of thethree-dimensional optical waveguide shown in the second embodiment (FIG.3), and description thereof is omitted. The structure of the left sideof the three-dimensional optical waveguide shown in FIG. 10 is oneobtained by vertically and horizontally reversing the structure of thethree-dimensional optical waveguide shown in the fourth embodiment (FIG.7). Here, a wavelength division multiplexing filter 1316 which is anexample of the wavelength division multiplexing filter of the presentinvention is set so as to transmit light of a wavelength λ1 and not totransmit light of a wavelength λ2.

[0173] In the three-dimensional optical waveguide having such astructure, when lights of the different wavelengths λ1 and λ2 aredirected into waveguides 1322 and 1332, respectively, the light of thewavelength λ1 directed into the waveguide 1322 reaches a reflectingsurface 1373 through a reflecting surface 1313, a lens 1334, an isolatorsubstrate 1308, a lens 1324, a reflecting surface 1363 and a waveguide1342. The light reflected by the reflecting surface 1373 passes througha lens 1344, the wavelength division multiplexing filter 1316 and a lens1364, is reflected by a reflecting surface 1393, and reaches a waveguide1362.

[0174] The light of the wavelength λ2 directed into the waveguide 1332reaches a reflecting surface 1383 through a reflecting surface 1333, alens 1304, the isolator substrate 1308, a lens 1314 and a reflectingsurface 1353. The light reflected by the reflecting surface 1383 isincident, through a lens 1354, on the wavelength division multiplexingfilter 1316 from the upper right in a slanting direction. Since thewavelength division multiplexing filter 1316 does not transmit light ofthe wavelength λ2, the light incident from the upper right of thewavelength division multiplexing filter 1316 in a slanting direction isreflected at the interface between the wavelength division multiplexingfilter 1316 and a lens substrate 1350, travels in a direction slantingupward toward the left, and is directed into a waveguide 1362 throughthe lens 1364 and the reflecting surface 1393.

[0175] When the lights of the wavelengths λ1 and λ2 are directed intothe waveguides 1322 and 1332 as described above, light having thewavelength components of λ1 and λ2 is output from the waveguide 1362. Asdescribed above, according to the present embodiment, a low-cost andhigh-performance three-dimensional optical waveguide is provided thatdoes not require a complicated adjustment although having a complicatedstructure.

[0176] (Seventh Embodiment)

[0177] Using any of the three-dimensional optical waveguides shown inthe above-described embodiments, a module transmitting and receivinglight can be formed. FIG. 19 is an example of the structure of such anoptical transmitter module. As shown in FIG. 19, to an electric inputterminal 1105 which is an example of the electric input terminal of thepresent invention, a laser diode 1109 which is an example of the lightemitting element of the present invention is connected. The laser diode1109 is connected to a waveguide 1102. The waveguide 1102 is connectedto a waveguide 1112 through an isolator 1108. To the waveguide 1112, anoptical output terminal 1107 which is an example of the optical outputterminal of the present invention is connected. Such an opticaltransmitter module can be formed, for example, by using thethree-dimensional optical waveguide shown in FIG. 1 which is an exampleof the three-dimensional optical waveguide of the present invention. Inthis case, the waveguide 1102 in FIG. 19 corresponds to the waveguide 2shown in FIG. 1, and to an end thereof, the laser diode 1109 (in thiscase, an edge emitting laser) is attached. The waveguide 1112 in FIG. 19corresponds to the waveguide 12 shown in FIG. 1, and at an end thereof,for example, a V groove 1042 shown in FIG. 25 is disposed as the opticaloutput terminal 1107, and an optical fiber cable (not shown) is fixed.

[0178] By doing this, an optical output can be output from the outputterminal 1107 in accordance with the electric signal input to theelectric input terminal 1105, so that a low-cost optical transmittermodule not requiring a complicated adjustment is provided.

[0179] Instead of using the three-dimensional optical waveguide shown inFIG. 1, the three-dimensional optical waveguide shown in FIG. 2 may beused. Moreover, the three-dimensional optical waveguide as shown in FIG.3 or FIG. 4 may be used. In that case, the two waveguides 22 and 32correspond to the waveguide 1102, and the two waveguides 312 and 302correspond to the waveguide 1112. At an end of each of the waveguides 22and 32, the laser diode 1109 is disposed, and to an end of each of thewaveguides 312 and 302, the optical output terminal 1107 is connected.The light emitted from each laser diode 1109 is output from the opticaloutput terminal 1107. Moreover, the three-dimensional optical waveguideshown in FIG. 5 may be used. In that case, the waveguide 1102 isomitted, and as the laser diode 1109, the surface emitting laser 59 isused.

[0180] Moreover, FIG. 20 shows an example of the structure of awavelength division multiplexing optical transmitter module. Thewavelength division multiplexing optical transmitter module shown inFIG. 20 has two laser diodes 1119 and 1129 each having the electricinput terminal 1105. To the laser diodes 1119 and 1129, the waveguides1132 and 1142 are connected, respectively. The waveguides 1132 and 1142are connected to waveguides 1152 and 1162 through an isolator 1118,respectively. The waveguides 1152 and 1162 are connected to the opticaloutput terminal 1107 through the wavelength division multiplexing filter1106.

[0181] Such a wavelength division multiplexing optical transmittermodule can be formed, for example, by using the three-dimensionaloptical waveguide of the structure shown in FIG. 10. In this case, thelaser diode 1119 outputting light of the wavelength λ1 is disposed at anend of the waveguide 1322, and the laser diode 1129 outputting light ofthe wavelength λ2 is disposed at an end of the waveguide 1332. Theoutput terminal 1107 is disposed at an end of the waveguide 1362.

[0182] By doing this, the electric signals input from the two laserdiodes 1119 and 1129 can be output as combined with each other as anoptical signal.

[0183] (Eighth Embodiment)

[0184]FIG. 21 shows an example of the structure of an optical receivermodule. As shown in FIG. 21, an optical input terminal 1117 (forexample, the V groove shown in FIG. 25) which is an example of theoptical input terminal of the present invention is disposed at an end ofa waveguide 1122, and a photodiode 1209 which is an example of the lightreceiving element of the present invention is connected to the waveguide1122. To the photodiode 1209, an electric output terminal 1115 which isan example of the electric output terminal of the present invention isconnected. Such an optical receiver module can be structured, forexample, by using the three-dimensional optical waveguide shown in FIG.6 which is an example of the three-dimensional optical waveguide.According to the optical receiver module having such a structure,electric output can be obtained from the electric output terminal 1115in accordance with the optical signal input to the optical inputterminal 1117.

[0185]FIG. 22 shows an example of the structure of a wavelength divisionmultiplexing optical receiver module. In this structure example, theoptical input terminal 1117 is connected to the wavelength divisionmultiplexing filter 1116, waveguides 1172 and 1182 are connected to thewavelength division multiplexing filter 1116, and photodiodes 1219 and1229 are connected to the waveguides 1172 and 118, respectively.

[0186] Such a wavelength division multiplexing optical receiver modulecan be structured, for example, by using the three-dimensional opticalwaveguide shown in FIG. 7. In this case, the optical input terminal 1117is connected to an end of the waveguide 72, and the photodiodes 1219 and1229 are connected to ends of the waveguides 712 and 702, respectively.The wavelength division multiplexing filter 76 is set so as to transmitlight of the wavelength λ1 and not to transmit light of the wavelengthλ2.

[0187] In the wavelength division multiplexing optical receiver modulehaving such a structure, when lights of the wavelength λ1 and thewavelength λ2 are directed into the waveguide 71, the light of thewavelength λ1 reaches the photodiode 1219 through the waveguide 712, thelight of the wavelength λ2 reaches the photodiode 1229 through thewaveguide 702, and in accordance therewith, electric output is outputfrom the electric output terminal 1115 connected to each of thephotodiodes 1219 and 1229. That is, an optical signal input from oneoptical input terminal 1117 can be obtained from each electric outputterminal 1115 as two separate electric signals.

[0188] The above-described optical transmitter module and opticalreceiver module can be used as an optical transmission system fortransmission and reception by being connected through an optical fibercable.

[0189] (Ninth Embodiment)

[0190]FIG. 23 shows an example of the structure of a wavelength divisionmultiplexing optical transmitter and receiver module having both anoptical transmission function and an optical reception function. In thestructure shown in FIG. 23, a laser diode 1139 having the electric inputterminal 1105 and emitting light of the wavelength λ1 is connected to awavelength division multiplexing filter 1126 which is an example of thewavelength division multiplexing filter of the present invention througha waveguide 1192, an isolator 1128 which is an example of the isolatorof the present invention and a waveguide 1212. The photodiode 1239having the electric output terminal 1115 and receiving light of thewavelength λ2 is connected to the wavelength division multiplexingfilter 1126 through a waveguide 1202. To the wavelength divisionmultiplexing filter 1126, an optical input and output terminal 1127 (forexample, the V groove shown in FIG. 25) which is an example of theoptical input and output terminal of the present invention is connected.

[0191] Such a wavelength division multiplexing optical transmitter andreceiver module can be structured, for example, by using thethree-dimensional optical waveguide shown in FIG. 9. In this case, theoptical input and output terminal 1127 is disposed at an end of thewaveguide 92. The wavelength division multiplexing filter 906 is set soas not to transmit light of the wavelength λ1 emitted from the surfaceemitting laser 99 and to transmit light of the wavelength λ2 input tothe optical input and output terminal 1127.

[0192] According to this structure, the light of the wavelength λ1emitted from the surface emitting laser 99 is reflected at the interfacebetween the wavelength division multiplexing filter 906 and the lenssubstrate 93, and is output from the optical input and output terminal1127 through the waveguide 92. The light of the wavelength λ2 input tothe optical input and output terminal 1127 passes through the wavelengthdivision multiplexing filter 906 to reach the surface-mount photodiode999. According to such a wavelength division multiplexing opticaltransmitter and receiver module, light can be transmitted and receivedwith only one optical input and output terminal 1127.

[0193]FIG. 24 shows an example of a light transmission apparatus usingsuch a wavelength division multiplexing optical transmitter and receivermodule. In FIG. 24, to the laser diode 1149, a laser diode driver IC1104 is connected, and to the laser diode driver IC 1104, a transmissionsignal multiplexer 1103 is connected. To the transmission signalmultiplexer 1103, an electric signal input terminal 1125 for inputting aplurality of signals is connected. The laser diode driver IC 1104controls the current bias supplied to the laser diode, and superimposesdigital signals.

[0194] On the other hand, to a photodiode 1249, a reception front end IC1114 is connected, and to the reception front end IC 1114, a receptionsignal demultiplexer 1113 is connected. To the reception signaldemultiplexer 1113, a reception signal output terminal 1135 foroutputting a plurality of signals is connected. The reception front endIC 1114 low-noise-amplifies the faint signal output from the photodiode1249.

[0195] In FIG. 24, the laser diode 1149 and the elements disposed on theright side of the photodiode 1249 are as described above. By using suchan optical transmission apparatus, a plurality of electric signals canbe transmitted on an optical fiber cable through one optical input andoutput terminal.

[0196] A plurality of the above-described optical modules fortransmission and reception can be used as an optical transmission systemfor transmission and reception by being connected through an opticalfiber cable. In this case, for example, two optical modules fortransmission and reception prepared as a pair can be used as a pair ofoptical transmission systems for transmission and reception by making asetting such that one optical transmitter and receiver module performstransmission at the wavelength λ1 and reception at the wavelength λ2 andthe other optical transmitter and receiver module performs transmissionat the wavelength λ2 and reception at the wavelength λ1.

[0197] While in the description given above, the top, the bottom, theright and the left are fixed to those shown in the figures, they may bedifferent from those described above as long as similar effects areobtained.

[0198] While in the description given above, light from a horizontaldirection is made to travel in the vertical direction or at an angle of45°, these are merely examples. The light may be made to travel at anarbitrary angle with respect to the laminated substrates. In that case,the angles of the reflecting surfaces and the arrangement of the lensesand the reflecting surfaces are settable so that the light travels insuch a manner.

[0199] While in the above-described embodiments, the substrates areformed of forming glass, the present invention is not limited thereto;they may be formed of resin or the like. The substrates may be formed,for example, by forming the markers 101 and 103 at the same timetogether with the waveguides on a silicon substrate by dry etching. Inthat case, similar effects to those described above are obtained.

[0200] In the above-described embodiments, the planar substrates otherthan the one having a waveguide may be sheet optical elements inaddition to or instead of the lens layer, the isolator layer and thefilter layer. Examples of such sheet optical elements include a sheetattenuator attenuating optical power.

[0201] According to the present invention, a low-cost three-dimensionaloptical waveguide not requiring a complicated adjustment can beprovided.

[0202] Moreover, when the planar waveguide, and the lens layer, theisolator layer or the filter layer are integrally formed on formingglass, a low-cost three-dimensional optical waveguide further notrequiring a complicated adjustment can be provided.

[0203] Moreover, when the planar substrate has the lens layer, theisolator layer or the filter layer, a high-performance three-dimensionaloptical waveguide can be provided.

[0204] Moreover, according to the method of manufacturing athree-dimensional optical waveguide of the present invention, a preciseand low-cost three-dimensional optical waveguide not requiring acomplicated adjustment can be provided.

[0205] Moreover, according to the optical module having thethree-dimensional optical waveguide of the present invention, a low-costoptical module not requiring a complicated adjustment can be provided.

What is claimed is:
 1. A three-dimensional optical waveguide comprisinga lamination of at least a planar substrate having a planar opticalwaveguide and a planar substrate having a sheet optical element.
 2. Athree-dimensional optical waveguide according to claim 1, wherein theplanar substrate having a sheet optical element is one of a lens layer,an isolator layer and a filter layer.
 3. A three-dimensional opticalwaveguide according to claim 2, wherein the planar substrate having theplanar waveguide, and the said one of the lens layer, the isolator layerand the filter layer are integrally formed on forming glass.
 4. Athree-dimensional optical waveguide according to claim 2 or claim 3,wherein a reflecting surface is formed on the planar optical waveguideand light passes through the said one of the lens layer, the isolatorlayer and the filter layer.
 5. A three-dimensional optical waveguideaccording to claim 4, further comprising at least one of a lightreceiving element and a light emitting element.
 6. A three-dimensionaloptical waveguide according to claims 1, wherein the planar substratesare positioned with respect to each other by markers integrally formedon at least two planar substrates.
 7. A method of manufacturing athree-dimensional optical waveguide comprising: providing a plurality ofplanar substrates, each having a planar optical waveguide; forming amarker on each of the planar substrates at a same time; and laminatingthe planar substrates by positioning the planar substrates by using themarkers.
 8. A method of manufacturing a three-dimensional opticalwaveguide according to claim 7, wherein the markers have one of aconcave or convex shape, and wherein before the planar substrates arelaminated, the planar substrates are positioned by applying light to themarkers and causing the light to be reflected or transmitted by themarkers.
 9. A method of manufacturing a three-dimensional opticalwaveguide according to claim 8, wherein bottom surfaces of the markersare one of inclined surfaces, scattering surfaces and lens surfaces. 10.An optical transmitter module, comprising: an electric input terminal; alight emitting element connected to the electric input terminal; thethree-dimensional optical waveguide according to claim 3, the waveguidetransmitting light emitted from the light emitting element; and anoptical output terminal outputting light transmitted through thethree-dimensional optical waveguide.
 11. An optical receiver module,comprising: an optical input terminal; the three-dimensional opticalwaveguide according to claim 3 connected to the optical input terminal;a light receiving element, that receives light transmitted through thethree-dimensional optical waveguide; and an electric output terminalconnected to the light receiving element.
 12. An optical transmitter andreceiver module, comprising: an electric input terminal; athree-dimensional optical waveguide including a lamination of at least aplanar substrate having a planar optical waveguide, a planar substratehaving an isolator, and a planar substrate having a wavelength divisionmultiplexing filter; a light emitting element connected to the electricinput terminal and connected to the three-dimensional optical waveguide;a light receiving element connected to the three-dimensional opticalwaveguide; an electric output terminal connected to the light receivingelement; and an optical input and output terminal connected to thethree-dimensional optical waveguide, wherein an electric signal inputfrom the electric input terminal is converted into an optical signal andtransmitted from the optical input and output terminal, and an opticalsignal received by the optical input and output terminal is convertedinto an electric signal and output to the electric output terminal. 13.An optical transmission system for transmission and reception,comprising: an optical transmitter module, including: an electric inputterminal; a light emitting element connected to the electric inputterminal; a three-dimensional optical waveguide having: a lamination ofat least a planar substrate having a planar optical waveguide connectedto the light emitting element and a planar substrate having a sheetoptical element; the waveguide is transmitting light emitted from thelight emitting element; and an optical output terminal outputting lighttransmitted through the three-dimensional optical waveguide; an opticalfiber cable connected to the optical transmitter module; and an opticalreceiver module, including: an optical input terminal; athree-dimensional optical waveguide having: a lamination of at least aplanar substrate having a planar optical waveguide connected to theoptical input terminal and a planar substrate having a sheet opticalelement; a light receiving element, that receives light transmittedthrough the three-dimensional optical waveguide; and an electric outputterminal connected to the light receiving element; the optical receivermodule is connected to the optical fiber cable.
 14. An opticaltransmission system for optical transmission and reception, comprising:the optical transmitter and receiver module according to claim 12; andan optical fiber cable connected to the optical transmitter and receivermodule.